import java.util.Scanner;

public class SecondQuestion {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        String[] str = {"zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine"};
        while (true) {
            System.out.println("请输入一个单词");
            String s = input.next();
            boolean flag = false;
            for (String str1 : str) {
                if (s.equals(str1)) {
                    flag = true;
                    break;
                }
            }
            if (flag ) {
                System.out.println("yes");
            } else {
                System.out.println("no");
            }

        }
    }
}